The Day Half of India Went Dark: July 30, 2012 Blackout

In a cascading failure of the northern electrical grid, millions plunged into darkness

In a cascading failure of the northern electrical grid, millions plunged into darkness

The blackout affected over 620 million people across 22 states—nearly half India’s population and about 9% of the world at that time

The blackout affected over 620 million people across 22 states—nearly half India’s population and about 9% of the world at that time

At 02:35 a.m. IST, the 400 kV Bina–Gwalior line tripped under overload, triggering widespread collapse

Major power stations shut down, causing an estimated 32 gigawatts of capacity loss

Trains stalled for hours, traffic lights failed, water systems shut down—Delhi metro and hospitals relied on backup generators 

By 08:00–09:00 a.m., essential services resumed and 80% power was restored in many areas within 15 hours

On July 31, the eastern and north-eastern grids also failed, amplifying the crisis across India

Weak inter-regional transmission plus high line loading and poor utility response were central to the blackout’s scale

India has since built the world’s largest unified grid with advanced monitoring systems—making such super‑blackouts virtually obsolete